1. A powder/granular material feeding device characterized by comprising: a hopper that receives powder/granular material; an outlet portion that discharges powder/granular material; a chute that guides, into the outlet portion, powder/granular material dropped from the hopper; and a stirring part that rotates a stirring member about a shaft protruding so as to tilt diagonally upward from a lower part of an interior of the chute.

2. The powder/granular material feeding device according to claim 1, characterized in that the shaft of the stirring part protrudes to a center of the interior of the chute in plan view. 3 . The powder/granular material feeding device according to claim 1 or 2, characterized in that the outlet portion contains a screw. 4 . The powder/granular material feeding device according to any one of claims 1 to 3, characterized in that the chute includes an inclined plane with an inner surface inclined diagonally upward, and the shaft is protruded from the inclined plane.

5. The powder/granular material feeding device according to claim 4, characterized in that the shaft of the stirring part is protruded perpendicularly to the inclined plane.

6. The powder/granular material feeding device according to claim 4 or 5, characterized in that the inclined plane of the chute is circular.

7. The powder/granular material feeding device according to any one of claims 1 to 6, characterized in that the hopper is oval and has a constant cross-sectional shape in a vertical direction. 8 . The powder/granular material feeding device according to claim 3, characterized in that the outlet portion includes a screw casing having an internal space, the internal space of the screw casing and a bottom space of the chute are linearly connected to each other, and the stirring member provided in the stirring part passes directly above a connected part of the spaces.

9. The powder/granular material feeding device according to any one of claims 1 to 8, characterized by further comprising a driving force transmission mechanism that transmits a driving force of a motor to the screw provided in the outlet portion and the stirring part, wherein the outlet portion and the stirring part are driven through the driving force transmission mechanism.

10. The powder/granular material feeding device according to any one of claims 1 to 9, characterized in that the chute includes the inclined plane with the inner surface inclined diagonally upward, a conical wall extended from an outer periphery of the inclined plane, and a side wall that connects the conical wall and the hopper to guide powder/granular material in the hopper to the conical wall of the chute.

11. The powder/granular material feeding device according to claim 10, characterized in that the side wall of the chute is oval in plan view and has a constant cross- sectional shape in the vertical direction.

12. The powder/granular material feeding device according to claim 10, characterized in that the side wall of the chute has a cross-sectional shape expanding in a lower part of the chute relative to an upper part.

13. The powder/granular material feeding device according to claim 12, characterized in that the side wall of the chute has a circular upper end in plan view.

14. The powder/granular material feeding device according to claim 13, characterized in that the hopper is circular and has a constant cross-sectional shape in the vertical direction.

POWDER/GRANULAR MATERIAL FEEDING DEVICE
Field of the Invention
The present invention relates to powder/granular
material feeding devices, and particularly relates to a
powder/granular material feeding device suitable for
quantitative feeding of powder/granular material.
Background of the Invention
Powder/granular material feeding devices, also called
feeders, have been widely known as devices for
quantitative feeding of powder/granular material. As
illustrated in FIGS. 20 and 21, such a powder/granular
material feeding device includes a hopper 51 that
receives powder/granular material, an outlet portion 52
having screws 52a for discharging powder/granular
material, a chute 53 that guides, into the outlet portion
52, powder/granular material dropped from the hopper 51,
and a stirring device 54 that is also called an agitator
for agitating powder/granular material in the chute 53
and the hopper 51. The powder/granular material feeding
device for quantitative feeding of powder/granular
material includes, in addition to these constituent
elements (the hopper 51, the outlet portion 52, the chute
53, and the stirring device 54), a metering unit 55 on
which these constituent elements are loaded, and a
control unit (not shown) that controls the outlet portion
52 so as to keep constant the weight of discharged
powder/granular material (the amount of discharged
powder/granular material) per hour or the weight of
powder/granular material in each discharge.
Various kinds of powder/granular material feeding
devices are available. The hopper 51 in FIGS. 20 and 21
is a cylinder that is vertically extended with a constant
shape in cross section. A hopper 82 in FIGS. 22, 23A, and

23B is shaped like a rectangular prism. A hopper 61 in
FIG. 24 has a curved shape, e.g., a conical or pyramidal
shape expanding upward in cross section. As simply
illustrated in FIG. 24, the curved hopper 61 expands
upward in cross section and can be advantageously reduced
in height with a sufficient capacity. However, the hopper
61 with a curved wall surface decreases in cross-
sectional area toward the bottom of the hopper 61,
causing bridging, that is, partially or entirely
remaining powder/granular material with high adhesion and
compressibility or a rathole that is a central hole of a
material. These phenomena are effectively avoided by
adopting a cylindrical hopper or hanging, as illustrated
in FIG. 24, a vertical agitator (stirring part) 62
downward into the hopper 61 from the top surface of the
hopper 61. A hopper agitator including such a vertical
agitator is disclosed in, for example, Japanese Patent
Laid-Open No. 9-216688.
Unfortunately, the provision of the vertical agitator
62 requires a space for lifting the agitator 62 during
cleaning of the hopper 61 (the hopper 61 is always
cleaned each time a powder/granular material type is
changed). Furthermore, a top surface 61a of the hopper 61
needs to be lifted with an additional weight of the
agitator 62 and an electric motor 63 for driving the
agitator, reducing workability of cleaning and so on. For
this reason, the agitator in general is not so popular
among users.
The chute provided under the hopper contains the
stirring device that is a mechanism for agitating
powder/granular material in the hopper on the chute to
prevent bridges in the hopper. A typical stirring device
is, as illustrated in FIGS. 20 and 21, a horizontal
agitator that has a stirring part (agitator) 54b for
vertically agitating powder/granular material with

respect to a shaft 54a protruding from the side of the
chute 53. Furthermore, as illustrated in FIG. 25, a
table-type powder/granular material feeding device is
available that rotates powder/granular material in a
circumferential direction by means of a stirring part 72
that is called a vertical agitator. The stirring part 72
rotates about a shaft 71d protruding upward from a bottom
71a of a chute 71. Moreover, as illustrated in FIGS. 22,
23A, and 23B, a powder/granular material feeding device
of flexible chute type is available in which a chute 81
disposed under the hopper 82 is made of flexible resin
and is deformed from the outside so as to move an
internal material.
The stirring device (stirring part) also supplies
powder/granular material into an outlet portion provided
under the stirring device and stabilizes the
powder/granular material with a high filling rate in the
outlet portion. The stable filling rate in the outlet
portion remarkably contributes to more stable discharging
capability and higher feeding accuracy (small variations).
The outlet portion is a screw-type outlet {double
screws or a single screw) using the screws 52a and a
screw 84 illustrated in FIGS. 21 to 23B. The outlet
portion may be vibration type, belt type, disk type, and
so on. However, the screw type is the most suitable for
powder/granular materials having various properties, e.g.,
adhesion and discharge. The single screw 84 (see FIGS. 22,
23A, and 23B) is preferably used for a less adhesive
material, whereas the double screws 52a (see FIG. 21)
capable of self-cleaning is preferably used for a highly
adhesive material. The double screws capable of
offsetting screw pulsations are frequently used for high
feeding accuracy.
Hence, the stirring part of the stirring device
disposed in the chute has the function of feeding a

material to the screw acting as the outlet portion under
the hopper as well as the function of preventing bridges
in the hopper disposed on the chute. The stirring part is
a mechanism that plays a key role in the powder/granular
material feeding device and is quite important in
determining the performance and character of the
powder/granular material feeding device.
The conventionally used powder/granular material
feeding devices of the respective types and the
advantages and disadvantages thereof will be specifically
described below.
FIGS. 20, 21, and 26 illustrate the powder/granular
material feeding devices, each having the horizontal
stirring part called a horizontal agitator. The two types
of powder/granular material feeding devices have the
dome-shaped chute 53 in FIGS. 20 and 21 and a square
chute 91 in FIG. 26. The rectangular-prism chute 91 in
FIG. 26 can be produced by boiler making (also called a
welded structure). A screw 92a with a flat driving side
and a flat discharging side allows the opening of the
chute 91 to have a relatively simple sealing structure
that advantageously facilitates sealing. Moreover, the
rectangular-prism chute 91 and a screw casing 92b that
accommodates the screws (outlet portion) 92a are linearly
in contact with each other, forming a long area of
feeding to the screws 92a. Thus, the powder/granular
material feeding device including the rectangular-prism
chute 91 can feed a material that is hard to come into
the screws 92a, for example, a film material.
However, a powder/granular material feeding device 90
disadvantageously requires welding over the corners of
the chute 91, is likely to deposit or leave a material on
the corners of the chute 91, and increases a screw length
as compared with the dome-shaped chute 53 (see FIG. 21),
forming a dual support structure. Moreover, a hopper (not

shown) disposed on the rectangular-prism chute 91 is
inevitably shaped like a rectangular prism, so that the
chute 91 and the hopper need to be joined with clamps at
several points. Disadvantageously, the attachment and
detachment of the hopper requires considerable effort and
time as compared with the dome-shaped chute. Reference
numeral 93 in FIG. 26 denotes the stirring part of the
horizontal agitator.
The powder/granular material feeding device with the
dome-shaped chute 53 in FIGS. 20 and 21 has no corners on
the chute 53, which reduces powder/granular material
deposition and residue and facilitates cleaning. The
cylindrical hopper 51 that hardly allows powder/granular
material deposition is attached on the upper part of the
chute 53, and a clamp band 56 can be used on a joining
area between the chute 53 and the hopper 51.
Advantageously, the hopper 51 can be attached and
detached with less effort and time.
However, the dome-shaped chute 5 3 provided in the
powder/granular material feeding device disadvantageously
needs to be manufactured with a mold, for example, by
drawing or a lost-wax process, so that the dome-shaped
chute 53 and a screw casing 52b that accommodates the
screws 52a are joined with a slightly complicated
configuration. Furthermore, the stirring part (agitator)
54b approaches closest to the screws 52a only at a center
point. A space is formed between an agitation range and
the screws 52a, and powder/granular material is fed to
the screws 52a with a shorter feeding area as compared
with the rectangular-prism chute, so that the
powder/granular material is less supplied to the screws
52a than in the rectangular-prism chute.
The powder/granular material feeding device having
the horizontal agitator vertically agitates
powder/granular material by means of the stirring part

54b or 93, vertically moving the powder/granular material
regardless of whether the chute is a rectangular prism or
a dome. Thus, in the case where the amount of discharged
powder/granular material is controlled during measurement,
the weight is likely to fluctuate. Particularly, the
powder/granular material feeding device is seriously
affected by fluctuations in weight during an operation
with a low flow rate and thus a control state may be
disturbed by the powder/granular material feeding device,
disadvantageously leading to lower feeding accuracy.
FIG. 25 is a perspective view illustrating the table-
type powder/granular material feeding device. In such a
powder/granular material feeding device, the bottom 71a
of the chute 71 is shaped like a round table. As has been
discussed, powder/granular material is agitated in the
circumferential direction by the stirring part 72 that is
called a vertical agitator. The stirring part 72 rotates
about the shaft 71d that protrudes upward from the bottom
71a of the chute 71. Reference numeral 71b in FIG. 25
denotes a chute outlet for feeding powder/granular
material to an outlet portion from the chute 71. In such
a so called table-type powder/granular material feeding
device, the bottom 71a of the chute 71 can have a
relatively large size, allowing a hopper (not shown) to
have a large base area. Since the stirring part 72
including the vertical agitator can be provided, bridges
can be effectively prevented. A joining area between the
chute 71 and the hopper is inevitably circular, allowing
the use of a clamp band similar to the clamp band 56 in
FIG. 21.
Even in the case of a granular material, e.g., a
pellet that does not need agitation, the simple stirring
part (agitator) 72 is necessary to prevent quite a large
amount of the material from remaining on the bottom 71a
shaped like a flat table. Also in the case of a powder

material, the material is deposited and left in a gap
between the stirring part 72 and the surface of the
bottom 71a and on the blade of the stirring part 72. A
screw 75 disposed directly under the bottom (table
surface) 71a is laterally shifted so as to avoid a
driving shaft that rotates the stirring part 72, limiting
an area of feeding to the screw 75. Moreover, the
stirring part 72 only passes above the screw, reducing
the capability of filling to the screw 75.
The screw 75 can be centered by providing another
room under the bottom (table surface) 71a. Moreover, the
provision of a stirring part (horizontal agitator) 73
around the screw 75 can improve the capability of filling
to the screw 75, though a large amount of powder/granular
material is left under the screw 75.
FIGS. 22, 23A, and 23B are a perspective view and
side cross-sectional views of a powder/granular material
feeding device 80 that includes the hopper 82 shaped like
a square cylinder (that is, a rectangular prism) on the
flexible chute 81. The side of the chute is deformed by a
paddle 83 from the outside of the flexible chute 81 to
move internal powder/granular material, thereby
preventing bridges. In the case of the rectangular-prism
hopper 82, powder/granular material having medium
flowability, e.g., calcium carbonate or talc is highly
unlikely to cause bridges. The rectangular-prism hopper
82 can be more easily manufactured than a conical or
pyramidal hopper in terms of the manufacturing cost,
leading to lower manufacturing cost. Furthermore, the
flexible chute type has a lower resistance than in the
rotations of a stirring part acting as a rotating object
in powder/granular material. Thus, the capacity of a
motor for driving the stirring part can be reduced,
achieving a clear cost advantage. Since the resistance is
low, the flexible chute 81 can have a larger size, so

that the hopper 82 can advantageously have a large
capacity with relative ease.
In the powder/granular material feeding device 8 0
including the flexible chute 81, however, the flexible
chute 81 is a consumable item that is an elastic body
made of resin or the like. Thus, the flexible chute 81
needs replacing every several years (e.g., two years),
requiring running cost for each replacement of the
flexible chute 81. Since the paddle 83 desirably comes
into contact with a flat surface, the flexible chute 81
and the hopper 82 have squares, which may lead to
deposition of a material on the corners of the hopper 82
so as to cause bridges. In other words, the capability of
preventing bridges is slightly lower than in the case
where the hopper 82 has a circle. Moreover, agitation by
the paddle 83 does not generate a force pressing a
material to the screw 84, so that the material is dropped
and inserted to the screw 84 only by its own weight. Thus,
the capability of filling a material to the screw 84 is
lower than in internal agitation. Since the flexible
chute 81 is vibrated by swinging of the paddle 83, the
weight is likely to fluctuate. In the case where the
amount of discharged powder/granular material is
controlled during measurement, the feeding accuracy may
decrease.
Disclosure of the Invention
As has been discussed, the conventional
powder/granular material feeding devices of any types
have advantages and disadvantages. Any of the
powder/granular material feeding devices does not fully
satisfy the function of sufficiently preventing bridges
and ratholes, the function of fully stabilizing the
filling rate of the outlet portion with a sufficient area
of feeding to the screw, and the function of suppressing

the amount of remaining powder/granular material. Some of
the powder/granular material feeding devices regularly
require consumable items such as the flexible chute 81 or
leave a large amount of powder/granular material in a
specific area inside the chute.
The present invention has been devised to solve the
problems. An object of the present invention is to
provide a powder/granular material feeding device that
fully satisfies the functions of sufficiently preventing
bridges and ratholes and fully stabilizing the filling
rate of an outlet portion without requiring consumable
items such as a flexible chute or leaving a large amount
of powder/granular material in a specific area inside the
chute.
In order to solve the problems, a powder/granular
material feeding device according to the present
invention is characterized by including: a hopper that
receives powder/granular material; an outlet portion that
discharges powder/granular material; a chute that guides,
into the outlet portion, powder/granular material dropped
from the hopper; and a stirring part that rotates a
stirring member about a shaft protruding so as to tilt
diagonally upward from the lower part of the interior of
the chute.
With this configuration, the stirring member rotates
about the shaft protruding so as to tilt diagonally
upward from the lower part of the interior of the chute.
Thus, powder/granular material is agitated diagonally,
that is, in various directions such as a vertical
direction and a circumferential direction by the stirring
member of the stirring part. This configuration
sufficiently agitates powder/granular material in the
chute and the hopper, thereby preventing the occurrence
of bridges and ratholes. Moreover, the track of rotation
of the stirring part can be located along the outlet

portion, thereby fully stabilizing the filling rate of
powder/granular material to the outlet portion.
Furthermore, in the case of weight measurement of
powder/granular material being discharged, the stirring
member rotating about the inclined shaft of the stirring
part can reduce vertical motions of agitated
powder/granular material and suppress fluctuations in
weight as compared with a horizontal agitator including a
stirring part that rotates in the vertical direction. The
outlet portion preferably contains a screw.
Furthermore, the powder/granular material feeding
device of the present invention is characterized in that
the shaft of the stirring part protrudes to the center of
the interior of the chute in plan view. This
configuration can sufficiently agitate powder/granular
material over the entire interior of the chute.
Moreover, according to the powder/granular material
feeding device of the present invention the chute
preferably includes an inclined plane with an inner
surface inclined diagonally upward, and the shaft is
preferably protruded from the inclined plane. Hence, the
chute and the stirring part can be disposed with a
relatively simple configuration. Since the shaft of the
stirring part is protruded perpendicularly to the
inclined plane, the seal structure of the inclined plane
of the chute and the shaft can be constructed with
relative ease, minimizing an increase in manufacturing
cost.
Preferably, the inclined plane of the chute is
circular. With this configuration, powder/granular
material can be sufficiently agitated and hardly remains
near a joining area between the inclined plane and the
side wall of the chute. Moreover, the hopper is oval and
has a constant cross-sectional shape in the vertical
direction, that is, an oval cylinder, thereby minimizing

the occurrence of bridges in the hopper without the need
for a vertical agitator.
Furthermore, the powder/granular material feeding
device of the present invention is characterized in that
the outlet portion includes a screw casing having an
internal space, the internal space of the screw casing
and the bottom space of the chute are linearly connected
to each other, and the stirring member provided in the
stirring part passes directly above the connected part of
the spaces. With this configuration, the bottom of the
chute and the screw casing are linearly connected,
thereby increasing the dimensions of a feed opening to
the screw. Moreover, the stirring member passes directly
above the overall feed opening to the screw while
pressing powder/granular material. This configuration
improves filling of powder/granular material into the
screw casing, stably keeping a high filling rate.
The powder/granular material feeding device according
to the present invention is characterized by further
including a driving force transmission mechanism that
transmits the driving force of a motor to the screw
provided in the outlet portion and the stirring part,
wherein the outlet portion and the stirring part are
driven through the driving force transmission mechanism.
This configuration can reduce the number of motors as
compared with the case where motors are used respectively
for the screw and the stirring part, achieving lower
manufacturing cost.
Furthermore, the powder/granular material feeding
device of the present invention is characterized in that
the chute includes the inclined plane with the inner
surface inclined diagonally upward, a conical wall
extended from the outer periphery of the inclined plane,
and a side wall that connects the conical wall and the

hopper to guide powder/granular material in the hopper to
the conical wall of the chute.
In this case, the side wall of the chute may be oval
in plan view and may have a constant cross-sectional
shape in the vertical direction. With this configuration,
the side wall of the chute can have a relatively simple
shape.
The side wall of the chute may have a cross-sectional
shape expanding in the lower part of the chute relative
to the upper part. With this configuration,
powder/granular material introduced from the hopper into
the chute is hardly compressed, so that a pressure on the
side wall of the chute decreases and powder/granular
material deposited on the side wall is likely to fall off
the side wall by its own weight. This can reliably
prevent bridges caused by powder/granular material
deposition on the side wall of the chute.
In this case, the side wall of the chute may have a
circular upper end in plan view, and the hopper may be
circular and have a constant cross-sectional shape in the
vertical direction. With this configuration, the hopper
can be circular. The hopper can be more easily formed
than an oval hopper. Furthermore, the hopper and the
chute can be easily connected with a simple structure
while the hopper can be connected to other members with a
simple structure.
According to the present invention, the stirring
member of the stirring part rotates about the shaft
protruding so as to incline diagonally upward from the
lower part of the interior of the chute, thereby
preventing the occurrence of bridges and ratholes.
Furthermore, the filling rate of powder/granular material
to the outlet portion can be sufficiently stabilized.
Even in the case where powder/granular material is
discharged during weight measurement, fluctuations in

weight can be suppressed, achieving high feeding accuracy.
Since the need for consumable items such as a flexible
chute can be eliminated, only small maintenance cost is
necessary. Moreover, the shaft protruding diagonally
upward allows the stirring member, e.g., a stirring blade
for agitation in the bottom of the chute to be
sufficiently supported on the base of the shaft.
Furthermore, the chute includes the inclined plane
that is directed diagonally upward, and the shaft
protruded from the inclined plane. Thus, the chute and
the stirring part can be disposed with a relatively
simple configuration. Moreover, the seal structure of the
inclined plane of the chute and the shaft can be
constructed with relative ease, suppressing the
manufacturing cost.
Since the inclined plane of the chute is circular,
powder/granular material can be sufficiently agitated and
hardly remains near the joining area between the inclined
plane and the side wall of the chute. Moreover, the oval
hopper has a constant cross-sectional shape in the
vertical direction, thereby minimizing the occurrence of
bridges in the hopper without the need for a vertical
agitator.
Furthermore, the internal space of the screw casing
provided in the outlet portion and the bottom space of
the chute are linearly connected to each other, and the
stirring member provided in the stirring part passes
directly above the connected part. This configuration
improves filling of powder/granular material into the
screw casing, stably keeping a high filling rate.
Consequently, the stability of discharge and the feeding
accuracy can be improved.
The side wall of the chute has a cross-sectional
shape expanding in the lower part of the chute relative
to the upper part. This configuration can satisfactorily

prevent powder/granular material deposition on the side
wall of the chute, thereby reliably preventing the
occurrence of bridges. Therefore, powder/granular
material can be stably discharged from the
powder/granular material feeding device, improving the
feeding accuracy and reliability of the powder/granular
material feeding device.
In this case, the upper end of the side wall of the
chute may be circular in plan view and the circular
hopper may have a constant cross-sectional shape in the
vertical direction. With this configuration, the hopper
can be circular and thus can be more easily formed than
an oval hopper. Furthermore, the hopper and the chute can
be easily connected with a simple structure while the
hopper can be connected to other members with a simple
structure, thereby reducing the manufacturing cost.
Brief Description of the Drawings
FIG. 1 is a front view illustrating a powder/granular
material feeding device according to a first embodiment
of the present invention;
FIG. 2 is a partial cutaway longitudinal side view of
the powder/granular material feeding device;
FIG. 3 is a plan view of the powder/granular material
feeding device;
FIG. 4 is a perspective view of the powder/granular
material feeding device viewed diagonally from the front;
FIG. 5 is a perspective view of the powder/granular
material feeding device viewed diagonally from the rear;
FIG. 6 is a front view illustrating a powder/granular
material feeding device according to a second embodiment
of the present invention;
FIG. 7 is a partial cutaway longitudinal side view of
the powder/granular material feeding device;

FIG. 8 is a plan view of the powder/granular material
feeding device;
FIG. 9 is a partial cutaway longitudinal side view
illustrating a powder/granular material feeding device
according to a third embodiment of the present invention;
FIG. 10 is a front view illustrating a
powder/granular material feeding device according to a
fourth embodiment of the present invention;
FIG. 11 is a partial cutaway longitudinal side view
of the powder/granular material feeding device;
FIG. 12 is a perspective view illustrating double
screws and so on;
FIG. 13 is a partial cutaway longitudinal side view
illustrating a powder/granular material feeding device
according to a fifth embodiment of the present invention;
FIG. 14 is a front view illustrating a
powder/granular material feeding device according to a
sixth embodiment of the present invention;
FIG. 15 is a partial cutaway longitudinal side view
of the powder/granular material feeding device;
FIG. 16 is a plan view of the powder/granular
material feeding device;
FIG. 17 is a perspective view of the powder/granular
material feeding device viewed diagonally from the front;
FIG. 18 is a perspective view of the powder/granular
material feeding device viewed diagonally from the rear;
FIG. 19 is a partial cutaway side view illustrating a
powder/granular material feeding device according to a
seventh embodiment of the present invention;
FIG. 20 is a perspective view illustrating a
conventional powder/granular material feeding device
including a cylindrical hopper and a horizontal agitator
(stirring part);
FIG. 21 is an exploded perspective view of the
conventional powder/granular material feeding device;

FIG. 22 is an exploded perspective view illustrating
another conventional powder/granular material feeding
device including a rectangular-prism hopper and a
flexible chute;
FIG. 23A is a longitudinal section of the other
conventional powder/granular material feeding device;
FIG. 23B is a longitudinal section of the other
conventional powder/granular material feeding device;
FIG. 24 is a longitudinal section illustrating a
conventional hopper agitator including a hopper and a
vertical agitator (stirring part), the hopper being
inclined so as to expand upward in cross section;
FIG. 25 is a partially exploded perspective view
illustrating the principle part of a conventional table-
type powder/granular material feeding device; and
FIG. 26 is a perspective view illustrating a
conventional powder/granular material feeding device
including a rectangular-prism hopper and a horizontal
agitator (stirring part).
Description of the Embodiments
A powder/granular material feeding device according
to embodiments of the present invention will be described
below with reference to the accompanying drawings. These
embodiments are merely exemplary and thus the present
invention is not always limited to these embodiments. In
the following explanation, a direction along which
powder/granular material is fed in an outlet portion will
be referred to as a forward direction.
As illustrated in FIGS. 1 to 5, a powder/granular
material feeding device according to a first embodiment
of the present invention includes a hopper 1 that
receives powder/granular material, an outlet portion 2
that discharges powder/granular material, a chute 3 that
guides, to the outlet portion 2, powder/granular material

dropped from the hopper 1, a stirring part 4 that rotates
stirring members 4b about a shaft 4a protruding so as to
incline diagonally upward from the lower part of the
interior of the chute 3, a metering unit 5 loaded with
these constituent elements, and a control unit (not
shown). Moreover, the top surface of the hopper 1 is
covered with a lid, which is not illustrated. The lid is
optionally connected to a powder/granular material feed
pipe and so on.
The hopper 1 and the upper part of the chute 3 (a
side wall 3c of the chute 3) are oval in plan view and
have a constant cross-sectional shape in a vertical
direction, that is, like an oval cylinder. Particularly,
on the rear side of the chute 3, an inclined plane 3a is
formed with an inner surface inclined diagonally upward
(that is, the inner surface inclined in the forward
direction). The stirring part 4 rotates the stirring
members 4b, which include stirring blades, about the
shaft 4a. In the present embodiment, the shaft 4a of the
stirring part 4 is extended perpendicularly to the
inclined plane 3a from the inclined plane 3a and
protrudes to the center of the interior of the chute 3 in
plan view.
The inclined plane 3a of the chute 3 has a round
shape. In the present embodiment, the stirring members 4b
of the stirring part 4 are respectively extended from two
points: the proximal end and the leading end of the shaft
4a in the radial direction of the inclined plane 3a.
Moreover, the ends of the stirring members 4b are
radially extended so as to incline along a conical wall
3b and the side wall 3c of the chute 3. In the present
embodiment, the two stirring members 4b of the stirring
part 4 are extended perpendicularly to each other in a
direction perpendicular to the shaft 4a at angles

differing from each other by 90 degrees each. The present
invention is not limited to this configuration.
The conical wall 3b of the chute 3 is conically
extended forward, laterally, and upward from the inclined
plane 3a. The ends of the stirring members 4b of the
stirring part 4 are rotated along the inner surface of
the conical wall 3b of the chute 3. The proximal ends of
the stirring members 4b of the stirring part 4 are
rotated along the inner surface of the inclined plane 3a
of the chute 3. The lower end of the side wall 3c of the
chute 3 is connected along the outer edge of the conical
wall 3b of the chute 3. The side wall 3c of the chute 3
is oval in plan view and is vertically extended upward
while keeping the shape of the lower end. The hopper 1 is
identical in shape to the side wall 3c of the chute 3 in
plan view and is extended upward. The upper end of the
chute 3 and the lower end of the hopper 1 can be joined
to each other with a clamp band 7, which is not
illustrated. Moreover, a gasket 8 is disposed between the
upper end of the chute 3 and the lower end of the hopper
1.
The outlet portion 2 is substantially cylindrical in
longitudinal section or has a spectacle shape that is
laterally extended. An outlet pipe 2a and a screw casing
2e, which are longitudinally extended, contain a single
rotatable screw 2b or double rotatable screws 2b (the
single screw 2b in FIGS. 1 to 6) . A longitudinally
extended part of the conical wall 3b of the chute 3 and
the upper edge of the screw casing 2e are linearly
connected and opened. The screw casing 2e is filled with
powder/granular material from the opening (also called a
feed opening). The end of the outlet pipe 2a is connected
to an exit pipe 2c that has an opening at the bottom.
Powder/granular material delivered into the exit pipe 2c

in the screw 2b is discharged downward (outside) from the
exit pipe 2c.
In the present embodiment, a motor 6 is provided
diagonally at the rear of the chute 3 and a worm gear 6a
is provided on the end of the drive shaft of the motor 6.
The shaft 4a of the stirring part 4 is protruded
diagonally downward from the outer surface of the
inclined plane 3a of the chute 3. A stirring part gear 4c
is attached to the end of a part protruding downward.
Furthermore, the rear end of the shaft of the screw 2b is
protruded from the rear end of the screw casing 2e. An
outlet gear 2d is attached to the protruded part of the
screw 2b. The stirring part gear 4c and the outlet gear
2d are engaged with the worm gear 6a attached to the end
of the drive shaft of the motor 6. Thus, the motor 6 is
driven to rotate the stirring members 4b of the stirring
part 4 and the screw 2b of the outlet portion 2 through
the stirring part gear 4c, the outlet gear 2d, and so on.
In other words, in the present embodiment, the worm gear
6a attached to the motor 6 and the stirring part gear 4c
and the outlet gear 2d that are engaged with the worm
gear 6a constitute a driving force transmission mechanism
that transmits the driving force of the motor 6 to the
screw 2b and the stirring members 4b of the stirring part
4. The screw 2b of the outlet portion 2 and the stirring
part 4 are driven through the driving force transmission
mechanism.
The constituent elements, specifically, the hopper 1,
the chute 3, the stirring part 4, and the outlet portion
2 are placed on the metering unit 5. The total weight of
the constituent elements and powder/granular material is
measured by the metering unit 5. The control unit (not
shown) controls the rotation speed of the screw 2b so as
to keep constant the weight of discharged powder/granular
material (the amount of discharged powder/granular

material) per hour or the weight of powder/granular
material in each discharge.
In this configuration, the motor 6 is driven to
rotate the stirring members 4b of the stirring part 4,
thereby agitating powder/granular material in the chute 3
and the lower part of the interior of the hopper 1. The
powder/granular material is then introduced into the
screw casing 2e from the lower part of the chute 3, is
passed through the outlet pipe 2a by the screw 2b, and is
discharged out of the exit pipe 2c.
In this case, the stirring members 4b of the stirring
part 4 rotate about the shaft 4a. The shaft 4a protrudes
so as to incline diagonally upward from the lower part of
the interior of the chute 3, achieving the advantages of
a so-called horizontal agitator type and a table type.
Since the shaft 4a of the stirring part 4 is disposed
in an inclined position, powder/granular material can be
sufficiently agitated by the stirring members 4b in
various directions including the vertical direction and a
circumferential direction. Moreover, the hopper 1 has a
constant cross-sectional shape, that is, a cylindrical
shape in the vertical direction. Hence, the occurrence of
bridges and ratholes in the chute 3 and the hopper 1 can
be quite satisfactorily prevented. Thus, in the case of
calcium carbonate or talc powder/granular material with
medium flowability as well as pellet or glass fiber
powder/granular material with high flowability, bridges
and ratholes can be prevented. Moreover, bridges and
ratholes can be satisfactorily prevented for materials
including titanium oxide that is likely to increase in
adhesion and compressibility with low flowability.
Furthermore, this configuration can eliminate the need
for a vertical agitator and so on, thereby effectively
preventing bridges and so on while suppressing an
increase in manufacturing cost with high cleaning

performance. This configuration can be reliably applied
to most kinds of powder/granular material.
The chute 3 and the outlet portion 2, specifically,
the bottom of the chute 3 and the screw casing 2e are
linearly connected (feed opening), thereby increasing the
dimensions of the feed opening to the screw 2b. Moreover,
the stirring members 4b pass directly above the overall
feed opening to the screw 2b while pressing
powder/granular material. This configuration improves
filling of powder/granular material into the screw casing
2e, stably keeping a high filling rate. Consequently, the
stability of discharge and the feeding accuracy can be
improved.
Moreover, this configuration hardly moves stirred
powder/granular material in the vertical direction as
compared with the stirring part of a horizontal agitator.
Thus, fluctuations in weight can be suppressed to obtain
a stable weight. This stabilizes the control state of the
powder/granular material feeding device that controls a
weight being measured, achieving high feeding accuracy.
Thus, the powder/granular material feeding device can be
used for feeding a small amount of powder/granular
material in an optimum condition.
The powder/granular material feeding device is
similar to the table-type powder/granular material
feeding device in FIG. 20 in that the shaft is protruded
from a surface near the bottom and rotor blades are
provided to rotate about the shaft. However, the
powder/granular material feeding device is different from
the table-type powder/granular material feeding device in
that the rotary stirring members 4b can scrape
powder/granular material substantially over the inclined
plane 3a and the conical wall 3b of the chute 3. Since a
space in the screw casing 2e is directly connected to the
conical wall 3b of the chute 3, only quite a small amount

of powder/granular material is left on the inner surface
of the conical wall 3b of the chute 3. Even in the case
where powder/granular material is deposited on, for
example, the stirring members 4b, the stirring members 4b
rotating in a tilted state facilitate falling of
powder/granular material, thereby preventing
powder/granular material from partially remaining on the
stirring members 4b.
The chute 3 including the inclined plane 3a, the
conical wall 3b, and the side wall 3c shaped like an oval
cylinder can be manufactured by boiler making (also
called a welded structure) without using molds. The chute
3 can be manufactured using molds. In this case, the
manufacturing cost of the chute 3 can be reduced by high
volume production.
As illustrated in FIG. 2, the rear of the lower part
of the chute 3 is inclined as if the rear was cut in side
view, thereby suppressing the length of the screw 2b.
Thus, the end of the screw 2b does not always need to be
supported. The manufacturing cost can be reduced by
eliminating bearings. Moreover, the screw 2b can be
reduced in diameter, allowing the powder/granular
material feeding device to be optimally used for feeding
a small amount of powder/granular material.
Some of the components of this configuration are
similar to those of the table-type powder/granular
material feeding device. As illustrated in FIG. 1, the
screw 2b can be located at the center of the
powder/granular material feeding device in front view.
Hence, the inlet and the outlet for powder/granular
material fed to the hopper 1 are located on the same
straight line, allowing a user to easily create an
installation plan of the powder/granular material feeding
device with higher convenience.

Furthermore, the shaft 4a protrudes diagonally upward
from the inclined plane 3a near the bottom of the chute 3,
allowing the stirring members 4b to be sufficiently-
supported and stably rotated on the base of the shaft 4a.
The shaft may be protruded from above to the bottom of
the chute 3 such that the stirring blades are fixed on
the end of the shaft. In this case, however, the stirring
blades attached to the end of the shaft may vibrate the
end of the shaft during rotations and cause unstable
rotations of the stirring blades. In contrast, in the
present embodiment, the stirring members 4b for agitation
near the bottom of the chute 3 can be particularly
sufficiently supported on the base of the shaft 4a, so
that the stirring members 4b can be stably rotated.
The shaft 4a of the stirring part 4 is protruded
perpendicularly to the inclined plane 3a, thereby
relatively easily constructing a seal structure of the
inclined plane 3a of the chute 3 and the shaft 4a of the
stirring part 4. This configuration can reduce the
manufacturing cost.
In the present embodiment, the inclined plane 3a of
the chute 3 is inclined at 45° with respect to a
horizontal line or the conveyance line of the screw 2b in
side view, and the shaft 4a protrudes perpendicularly to
the inclined plane 3a. In this case, the stirring members
4b can sufficiently agitate powder/granular material in
the vertical direction and particularly, in the
circumferential direction. The inclination angle of the
inclined plane 3a is not limited to 45°. As illustrated
in FIGS. 6 to 8, a shaft 4a may be inclined at more than
45°, for example, 60° with respect to a horizontal line or
may be inclined at less than 45°, for example, 30° (not
shown) with respect to the horizontal line {a
powder/granular material feeding device according to a
second embodiment of the present invention).

In the above-described embodiment, the relatively-
large inclined plane 3a is formed in the rear of the
lower part of the chute 3. The present invention is not
limited to this configuration. As illustrated in FIG. 9,
a shaft 4a may protrude diagonally upward substantially
from a corner in the rear of the lower part of a chute 3
such that stirring members 4b rotate about the shaft 4a
along a conical wall 3b of the chute (a powder/granular
material feeding device according to a third embodiment
of the present invention).
In the above-described embodiment, the stirring
members 4b of the stirring part 4 are extended from two
points: the base and end of the shaft 4a. The present
invention is not limited to this configuration. As
illustrated in FIG. 9, the stirring members 4b may be
extended to two sides from a point of the shaft 4a.
Alternatively, as illustrated in FIGS. 10 and 11, a shaft
4a may be further protruded upward with stirring members
4b provided at three points (or at least three points).
Moreover, in the above-described embodiment, the stirring
members 4b are extended in the radial direction. The
present invention is not limited to this configuration.
The stirring members 4b provided at any intervals in a
circumferential direction may be extended in multiple
directions (at least three directions, a powder/granular
material feeding device according to a fourth embodiment
of the present invention).
In the drawings of the above-described embodiments,
the single screw 2b is illustrated. As has been discussed,
double screws 2b in FIG. 12 may be optionally disposed
instead.
In the above-described embodiment, the driving force
transmission mechanism including the worm gear 6a, the
stirring part gear 4c, and the outlet gear 2d is provided
to transmit the driving force of the single motor 6 to

the screw 2b of the outlet portion 2 and the stirring
part 4. The screw 2b of the outlet portion 2 and the
stirring part 4 are driven through the driving force
transmission mechanism. This configuration only requires
the single motor, advantageously reducing the
manufacturing cost.
The present invention is not limited to this
configuration. As illustrated in FIG. 13, a motor 11 for
rotating a screw 2b of an outlet portion 2 and a motor 12
for rotating a stirring part 4 may be separately provided
(a powder/granular material feeding device according to a
fifth embodiment of the present invention). In this case,
the number of motors 11 and 12 leads to higher
manufacturing cost. However, the screw 2b of the outlet
portion 2 and the stirring part 4 can be separately
driven or controlled with different adjusted rotation
speeds.
In these embodiments, the side wall 3c of the chute 3
is oval in plan view and has a constant cross-sectional
shape in the vertical direction. The present invention is
not limited to this configuration. FIGS. 14 to 18
illustrate a powder/granular material feeding device
according to a sixth embodiment of the present invention.
As illustrated in these drawings, a side wall 3c of a
chute 3 in the powder/granular material feeding device
expands in the lower part of the chute in cross section
relative to the upper part. As illustrated in FIG. 14 and
so on, in the powder/granular material feeding device,
the left side wall 3c and the right side wall 3c of the
chute 3 expand in the lower part of the chute in front
view. As illustrated in FIG. 15, the side wall 3c on the
front end and the side wall 3c on the rear end are formed
like vertical straight lines in side view. The side walls
3c are seamlessly connected in circumferential and
vertical directions. Moreover, in the present embodiment,

the upper end of the side wall 3c of the chute 3 is
circular in plan view (perfect circle) and a hopper 1 is
a cylinder (perfect circle) as large as the upper end of
the side wall 3c of the chute 3. The hopper 1 has a
constant cross-sectional shape in the vertical direction.
With this configuration, the side wall 3c of the
chute 3 expands in the lower part of the chute in cross
section relative to the upper part. Thus, powder/granular
material introduced from the hopper 1 into the chute 3 is
hardly compressed, so that a pressure on the side wall 3c
of the chute 3 decreases and powder/granular material
deposited on the side wall 3c is likely to fall off the
side wall 3c by its own weight. This configuration can
satisfactorily prevent powder/granular material
deposition on the side wall 3c of the chute 3. Since the
hopper 1 and the upper end of the chute 3 are circular in
plan view, a degree of curving is kept constant but is
not locally increased unlike in the case of an oval shape
in plan view, thereby satisfactorily preventing
powder/granular material deposition on the side wall 3c
of the chute 3. This configuration can prevent the
occurrence of bridges in the chute 3 with higher
reliability, stabilize the weight of powder/granular
material discharged from the powder/granular material
feeding device, and stabilize the rate of filling into a
screw 2b of an outlet portion 2 provided under the chute
3, thereby improving the accuracy of feeding and
reliability of the powder/granular material feeding
device.
In this configuration, the hopper 1 and the upper end
of the chute 3 are circular in plan view. Thus, the
hopper 1 can be more easily formed than the oval hopper 1.
Furthermore, the hopper 1 and the chute 3 can be
connected to each other with a simple structure, and the

hopper can be also connected to other members with a
simple structure, thereby reducing the manufacturing cost.
In the present embodiment, the powder/granular
material feeding device is a screw feeder including the
screw 2b provided in the outlet portion 2. The present
invention is not limited to this configuration. As
illustrated in FIG. 19, the outlet portion 2 may be a
feeder device including a belt-type feeder 13 (a
powder/granular material feeding device according to a
seventh embodiment of the present invention). The present
invention is also applicable to a powder/granular
material feeding device including an outlet portion with
an on-off valve.

We Claim:
1. A powder/granular material feeding device
characterized by comprising:
a hopper that receives powder/granular material;
an outlet portion that discharges powder/granular
material;
a chute that guides, into the outlet portion,
powder/granular material dropped from the hopper; and
a stirring part that rotates a stirring member about
a shaft protruding so as to tilt diagonally upward from a
lower part of an interior of the chute.
2. The powder/granular material feeding device according
to claim 1, characterized in that the shaft of the
stirring part protrudes to a center of the interior of
the chute in plan view.
3 . The powder/granular material feeding device according
to claim 1 or 2, characterized in that the outlet portion
contains a screw.
4 . The powder/granular material feeding device according
to any one of claims 1 to 3, characterized in that the
chute includes an inclined plane with an inner surface
inclined diagonally upward, and the shaft is protruded
from the inclined plane.

5. The powder/granular material feeding device according
to claim 4, characterized in that the shaft of the
stirring part is protruded perpendicularly to the
inclined plane.
6. The powder/granular material feeding device according
to claim 4 or 5, characterized in that the inclined plane
of the chute is circular.

7. The powder/granular material feeding device according
to any one of claims 1 to 6, characterized in that the
hopper is oval and has a constant cross-sectional shape
in a vertical direction.
8 . The powder/granular material feeding device according
to claim 3, characterized in that the outlet portion
includes a screw casing having an internal space, the
internal space of the screw casing and a bottom space of
the chute are linearly connected to each other, and the
stirring member provided in the stirring part passes
directly above a connected part of the spaces.
9. The powder/granular material feeding device according
to any one of claims 1 to 8, characterized by further
comprising a driving force transmission mechanism that
transmits a driving force of a motor to the screw
provided in the outlet portion and the stirring part,
wherein the outlet portion and the stirring part are
driven through the driving force transmission mechanism.
10. The powder/granular material feeding device according
to any one of claims 1 to 9, characterized in that the
chute includes the inclined plane with the inner surface
inclined diagonally upward, a conical wall extended from
an outer periphery of the inclined plane, and a side wall
that connects the conical wall and the hopper to guide
powder/granular material in the hopper to the conical
wall of the chute.
11. The powder/granular material feeding device according
to claim 10, characterized in that the side wall of the
chute is oval in plan view and has a constant cross-
sectional shape in the vertical direction.

12. The powder/granular material feeding device according
to claim 10, characterized in that the side wall of the
chute has a cross-sectional shape expanding in a lower
part of the chute relative to an upper part.
13. The powder/granular material feeding device according
to claim 12, characterized in that the side wall of the
chute has a circular upper end in plan view.
14. The powder/granular material feeding device according
to claim 13, characterized in that the hopper is circular
and has a constant cross-sectional shape in the vertical
direction.